The present invention relates to an arrangement for transferring carriers at a power line discontinuous portion of power-and-free trolley conveyors.
At a power line discontinuous portion of power-and-free trolley conveyors, a pusher dog restraining guide rail is usually disposed at one side of the terminal end of a carrier entering power line as disclosed, for example, in Japanese Pat. No. 820,109 having Publication No. 48-22751. When a pusher dog in engagement with a tilting dog on the front free trolley of a carrier to pull along the carrier is disengaged from the dog, another pusher dog following the dog comes into striking contact with a rear end slope of a cam mounted on the rear free trolley of the same carrier, with a side projection of the following pusher dog brought into bearing contact with the lower face of the guide rail, so that the carrier is pushed forward from behind by the propelling force of the following pusher dog. With the conventional arrangement described above, however, the frictional contact between the side projection on the pusher dog rapidly wears away the two members, rendering the carrier transferring arrangement unserviceable for a prolonged period of time. In view of the above problem, it is known to mount a roller on the forward end of the side projection on the pusher dog and to make the roller rollable on the lower face of the guide rail to reduce the wear on the members, but this arrangement involves the necessity of attaching a roller to the side projection of every pusher dog, hence very cumbersome and economically disadvantageous. The arrangement has another problem in that the roller interferes with the disengagement of the pusher dog from the tilting dog on the front free trolley of the carrier.